The present invention relates to a base for rendering a gas-fired water heater explosion-proof by elevating the water heater and its combustion chamber from a floor surface and by using vapour detector(s) to detect the presence of combustible vapours before they can reach the combustion chamber.
Gas water heaters are provided with a combustion chamber in the lower part thereof where a gas burner is located to heat the bottom tank wall of the water heater to produce hot water. The combustion chamber has openings whereby to admit fresh air for mixture with the gas to produce a combustible product. These gas water heaters can be hazardous if they are utilized in areas where there is a risk that combustible vapours may propagate in the area of the air supply to the burners. Usually, combustible vapours will accumulate on a floor surface, because they are heavier than air, and slowly build up and rise thus creating a large cloud of ignitable gas vapours. If such a cloud of vapour propagates to the combustion chamber of a gas water heater it will ignite and cause a very serious explosion and usually destroy the gas water heater and fragment the gas line to add further fuel to the fire. Needless to say, such explosion would be disastrous to any person in the immediate vicinity of the gas water heater and cause a building fire.
Gas water heaters can be installed in garages. However, in garages fumes are usually released by automobiles due to gas leakage or the storage of paint or the use of glues and other such combustible vapour generating products that we usually find in work areas of a garage. The basement of a residence is also another hazardous location where dangerous products are stored. In the past, various attempts have been made to deal with this problem but to date none has proven satisfactory.
It is known to provide sealed combustion chambers and provide duct work whereby to admit fresh air from the outside into these chambers for the combustible products. We usually find such installations in gas fireplaces and these fire places are usually installed close to an outside wall for this purpose. The chimney duct work of these gas appliances are usually formed by concentric piping wherein the centre pipe is used as a flue and the annular channel thereabout formed by the spaced outer pipe acts as the fresh air intake to the combustion chamber. This process in water heater is known as xe2x80x9cdirect vent water heaterxe2x80x9d and has been widely used for more than six years. Wall distance from the appliance is the limitation of the application.
There is currently millions of gas water heaters in operation and most of these are fed combustible air through the base of the housing of the water heater and they are subjected to the above-mentioned problems.
It is a feature of the present invention to provide a base for rendering a gas water heater substantially explosion-proof.
Another feature of the present invention is to provide a base which is adaptable to existing water heaters whereby to provide a retrofit to elevate the water heaters from a floor support surface and wherein vapour detectors are associated with the base to render the water heater substantially explosion-proof by early switching off the gas supply and extinguishing the burner, the pilot flames and cooling the components in the combustion chamber.
Another feature of the present invention is to provide a base and a connector whereby to secure the base to existing gas water heaters to support the water heaters elevated from a floor support surface and wherein detecting and switching means is provided to shut off the gas supply to the burner of the combustion chamber and pilot and burner flames upon detection of combustible vapours.
According to the above features, from a broad aspect, the present invention provides a base for rendering a gas-fired water heater, having a lower combustion chamber, explosion-proof. The base has elevating support means to support the water heater elevated from a floor surface. One or more vapour detectors are associated with the base to detect the presence of combustible vapours. The vapour detectors are connected to switching means to shut-off a gas burner and pilot in the combustion chamber before the combustible vapour reach the gas burner and pilot through combustion chamber air supply passages in a lower end of the gas water heater housing.